# LINQ Average Method in C#

## LINQ Average Method in C# with Examples

In this article, I will discuss the LINQ Average Method in C# with Examples. Please read our previous article before proceeding to this article, where we discussed the LINQ Min Aggregate Method in C# with Examples. The LINQ  Average Method belongs to the category of Aggregate Operators. As part of this article, we will discuss the following pointers.

1. What is the LINQ Average Method in C#?
2. Example to Understand Average Method in C#
3. LINQ Average Method with Where Extension Method using C#
4. How to use LINQ Average Method with Predicate in C#
5. LINQ Average Method with Complex Type in C#
6. When to Use the LINQ Average Method in C#?
##### What is the LINQ Average Method in C#?

The LINQ Average method calculates the average value of a numeric collection or the average of a numeric property of objects in a collection. It’s a part of the System.Linq namespace can be used with any IEnumerable<T> or IQueryable<T> collection where T is a numeric type or can be projected to a numeric type.

##### Example to Understand Average Method in C#:

Let us understand the LINQ Average method with Examples using C#. The following example calculates the average of all integers present in the integer collection using Query and Method syntax. The point that you need to remember is that the Average Method will work with numeric values only. In this case, the collection stores integer values so that we can apply the LINQ Average Method. We don’t have any operator called average in the LINQ query syntax. So here, we need to use mixed syntax.

```using System;
using System.Linq;
namespace LINQDemo
{
class Program
{
static void Main(string[] args)
{
int[] intNumbers = new int[] { 60, 80, 50, 90, 10, 30, 70, 40, 20, 100 };

//Using Method Syntax
var MSAverageValue = intNumbers.Average();

//Using Query Syntax
var QSAverageValue = (from num in intNumbers
select num).Average();

Console.WriteLine("Average Value = " + MSAverageValue);
}
}
}
```

Output: Average Value = 55

##### Example to Understand LINQ Average Method with Where Extension Method using C#

Let us see an example to Understand how we can use the LINQ Average Method and the Where Extension Method in C# using both Method and Query Syntax. Now, our requirement is to calculate the average of all numbers greater than 50. The following example code exactly does the same.

```using System;
using System.Linq;
namespace LINQDemo
{
class Program
{
static void Main(string[] args)
{
int[] intNumbers = new int[] { 60, 80, 50, 90, 10, 30, 70, 40, 20, 100 };

//Using Method Syntax
var MSAverageValue = intNumbers.Where(num => num > 50).Average();

//Using Query Syntax
var QSAverageValue = (from num in intNumbers
where num > 50
select num).Average();

Console.WriteLine("Average Value = " + MSAverageValue);
}
}
}
```

Output: Average Value = 80

##### Example to Understand How to use LINQ Average Method with Predicate in C#

Let us see an example of using the LINQ Average Method with Predicate in C# using both Method and Query Syntax. Instead of using the Where Extension method to filter the data, we can also use the other overloaded version of the Average method, which takes a Predicate as a parameter. Within that predicate, we can write the logic to filter the data.

In the example below, within the Average Method, we use a Predicate and provide the condition of whether the number is greater than 50. If the number is greater than 50, then we are returning true; else, we are returning false. The following example will calculate the average of all integers greater than 50.

```using System;
using System.Linq;
namespace LINQDemo
{
class Program
{
static void Main(string[] args)
{
int[] intNumbers = new int[] { 10, 30, 50, 40, 60, 20, 70, 90, 80, 100 };

//Using Method Syntax with a Predicate
var MSAverageValue = intNumbers.Average(num => {
if (num > 50)
return num;
else
return 0;
});

//Using Query Syntax with a Predicate
var QSAverageValue = (from num in intNumbers
select num).Average(num => {
if (num > 50)
return num;
else
return 0;
});

Console.WriteLine("Average Value = " + QSAverageValue);

}
}
}```

Output: Average Value = 40

##### Points to Consideration:
• Ensure the collection is not empty to avoid InvalidOperationException. You might want to check if the collection is empty or use DefaultIfEmpty with a default value.
• Be aware of potential issues with floating-point precision when averaging floating-point numbers.
• In the case of collections of custom objects, ensure that the property you’re averaging is not null to avoid null reference exceptions.
##### Example to Understand LINQ Average Method with Complex Type in C#:

Let us see an example of using the LINQ Average Method with Complex Type in C# using both Method and Query Syntax. We are going to work with the following Employee class. As you can see, it is a very simple Employee class with four properties: ID, Name, Salary, and Department. Here, we also created one method, i.e., GetAllEmployees(), which will return the list of all the employees, which will be our data source.

```using System.Collections.Generic;
namespace LINQDemo
{
public class Employee
{
public int ID { get; set; }
public string Name { get; set; }
public int Salary { get; set; }
public string Department { get; set; }

public static List<Employee> GetAllEmployees()
{
List<Employee> listStudents = new List<Employee>()
{
new Employee{ID= 101,Name = "Preety", Salary = 10000, Department = "IT"},
new Employee{ID= 102,Name = "Priyanka", Salary = 15000, Department = "Sales"},
new Employee{ID= 103,Name = "James", Salary = 50000, Department = "Sales"},
new Employee{ID= 104,Name = "Hina", Salary = 20000, Department = "IT"},
new Employee{ID= 105,Name = "Anurag", Salary = 30000, Department = "IT"},
new Employee{ID= 106,Name = "Sara", Salary = 25000, Department = "IT"},
new Employee{ID= 107,Name = "Pranaya", Salary = 35000, Department = "IT"},
new Employee{ID= 108,Name = "Manoj", Salary = 11000, Department = "Sales"},
new Employee{ID= 109,Name = "Sam", Salary = 45000, Department = "Sales"},
new Employee{ID= 110,Name = "Saurav", Salary = 25000, Department = "Sales"}
};

return listStudents;
}
}
}```

Now, our requirement is to calculate the Average Salaries of all the Employees. The following example calculates the Average Salaries of all employees using the LINQ Average method with both Method and Query Syntax. Here, we specify the numeric Salary column using a lambda expression to the Average method.

```using System;
using System.Linq;
namespace LINQDemo
{
class Program
{
static void Main(string[] args)
{
//Using Method Syntax
var MSAverageSalary = Employee.GetAllEmployees()
.Average(emp => emp.Salary);

//Using Query Syntax
var QSAverageSalary = (from emp in Employee.GetAllEmployees()
select emp).Average(e => e.Salary);

Console.WriteLine("Average Salary = " + MSAverageSalary);
}
}
}```

Output: Average Salary = 26600

##### Example using Average and Where Extension Method in C#:

Let us see an example of using both LINQ Average and Where Extension Methods with Complex Type using Method and Query Syntax. Our requirement is to calculate the average salary of all the employees who belong to the IT department. The following example exactly does the same. Using the Where Extension Method, we are filtering the IT department employees, and using the Average method, we are specifying the Salary numeric column, which will calculate the average salary of IT department employees.

```using System;
using System.Linq;
namespace LINQDemo
{
class Program
{
static void Main(string[] args)
{
//Using Method Syntax
var MSAverageSalary = Employee.GetAllEmployees()
.Where(emp => emp.Department == "IT")
.Average(emp => emp.Salary);

//Using Query Syntax
var QSAverageSalary = (from emp in Employee.GetAllEmployees()
where emp.Department == "IT"
select emp).Average(e => e.Salary);

Console.WriteLine("IT Department Average Salary = " + MSAverageSalary);
}
}
}```

Output: IT Department Average Salary = 24000

Let’s rewrite the previous example using the custom predicate. As you can see, within the Average method, we are checking the Department property value, and if the Department is It, we are returning the corresponding Salary; else, we are returning null.

```using System;
using System.Linq;
namespace LINQDemo
{
class Program
{
static void Main(string[] args)
{
//Using Method Syntax and Predicate
var TotalSalaryMS = Employee.GetAllEmployees()
.Average(emp => {
if (emp.Department == "IT")
return emp.Salary;
else
return null;
});

Console.WriteLine("IT Department Total Salary = " + TotalSalaryMS);

}
}
}```

Output: IT Department Average Salary = 24000

##### When to Use the LINQ Average Method in C#?

Here are some common situations when you should use the Average method:

• Calculating Average Values: Use the Average method to determine the average value of numeric data points, such as grades, scores, prices, or measurements.
• Data Analysis: In data analysis and statistics, you can use the Average method to calculate the mean value of a data set, which provides insights into the central tendency of the data.
• Grades or Scores: When working with educational data or assessment results, you can use the Average method to compute a group of students’ average grades or scores.
• Financial Calculations: In financial applications, the Average method can be used to calculate the average price, rate of return, or other financial metrics from historical data.
• Sensor Data Processing: When dealing with sensor data, such as temperature readings or sensor measurements, you can use the Average method to calculate the average value over a period of time.
• Stock Market Analysis: In stock market analysis and trading algorithms, the Average method can help compute moving averages, which is essential for trend analysis.
• User Ratings and Reviews: In applications that involve user ratings or reviews, you can use the Average method to determine the average rating or sentiment score.
• Performance Metrics: When analyzing the performance of systems or processes, you can use the Average method to calculate average response times, throughput, or other performance metrics.

In the next article, I will discuss the LINQ Count Method in C# with Examples. I hope you understand the use and need of the LINQ Average Method in C# with Examples.